Story by DS Davidson. Set in March 1969, during the early days of UNIT. The Brigadier is sent to investigate the disappearance of Under-Secretary Sir William Standish after he vanishes following an inspection of the reopened Lackley Asylum. There, they discover a plot by the Great Intelligence to send the entire world insane. Published in Monomyth 28.
- The story was accompanied by a Yeti illustration by DJ Tyrer that was based on the Harlequin miniature. It was also accompanied by a suitably insane-seeming picture by AC Evans and fitted, thematically, with the cover: The Madhouse, also by AC Evans.
- The exact spelling of Sanatarium varies, although Sanatorium is more common. The word was a socially-acceptable term for a psychiatric hospital, but correctly referred to a TB hospital.
- Given the mutability of the term (see above), it was perhaps inevitable that the title caused confusion! When written, it was actually spelled Sanitarium (also without The), while in the issue's contents it appears as The Sanatarium (as used here) – whereas in the actual title printed above the story it is given as The Sanatorium. The title of this wiki entry used all three forms at some point. Both DJ Tyrer and DS Davidson were ready for a spell in a sanitorium by the time they were done going over all this!